1. Field of the Invention
This invention relates to a photocatalyst dispersing element, a method for manufacturing a photocatalyst dispersing element, a photocatalyst element, and a method for manufacturing a photocatalyst element.
2. Background Art
In recent years, a photocatalyst material as represented by titanium dioxide has gathered attention. “Photocatalyst material” is a substance that has a semiconductor-like physical property, enters into an excited state by being irradiated with light having larger energy than the band gap energy between the conduction band and the valence band and generates a pair of electron and hole.
Titanium dioxide is photoexcited by being irradiated with light having a wavelength of 387 nm or less and a pair of electron and hole is generated inside. Thereby, the pair of electron and hole generates reactive oxygen species such as hydroxyl group radical or superoxide ion on the surface of the photocatalyst material and in the vicinity thereof, and then the oxidative active oxygen species cause degradation activity or hydrophilization. And, utilization of these actions can generate self-cleaning action, deodorization action, antibacterial action, and so forth, and therefore, various members and product groups provided with the photocatalyst materials have been proposed.
Moreover, in the case of titanium dioxide that is a representative photocatalyst material, its main excitation light is ultraviolet, and thereby, there is a problem that sufficient performance cannot be obtained in a room with little ultraviolet. Therefore, the photocatalyst material of so-called visible light response type is being investigated, and there are tungsten oxide and cadmium sulfide as the representative substances.
In using such a photocatalyst material for various materials or product groups or the like, it is necessary to provide the photocatalyst material on the surface of a substrate. In this case, it is convenient that the liquid or the like containing the photocatalyst material is preliminarily produced and applied to the surface of the substrate.
Therefore, a liquid or cream containing the photocatalyst material has been proposed (see, JP-A 11-1620 (Kokai)(1999), JP-A 2002-212464 (Kokai)). However, in these techniques, dispersibility of the photocatalyst material in the association with the degree of catalytic activity of the photocatalyst material has not been considered. Therefore, it is feared that the photocatalyst materials aggregates one another and that the dispersion becomes nonuniform. Also, it is feared that the degree of catalytic activity of the photocatalyst material lowers.